[mythtv-users] Quality difference between software only and Nvidia XvMC

[Erik Burrows]

Thanks Michael,
VDPAU is indeed superior. Playing 1080i content, my CPU utilization is
down by more than half, and the quality is indistinguishable from
software decoding. 

VDPAU is interesting in one other aspect though: Overlapping window
movements leave ghosts in the video display, until I give the display
window focus again. Not really a problem, but an interesting artifact of
graphical off-loading.

Thanks,
  -Erik

On Sun, 2010-03-07 at 01:30 -0500, Michael T. Dean wrote:
> On 03/06/2010 06:46 PM, Erik Burrows wrote:
> > I have a mythtv front-end with a Nvidia Quadro FX 580. I've been happily
> > using it to display 1080i content captured via firewire from cable.
> > Worked great, no issues.
> >
> > Today I looked into taking full advantage of the Nvidia chipset's XvMC
> > capability. Following the instructions at
> > http://www.mythtv.org/wiki/XvMC, I got it working. Happily, my cpu
> > utilization was cut by more than half, which is great.
> >
> > What was not so great, was that the quality of the video playback
> > suffered. I saw more jitter in the images, and more compression
> > artifacts.
> >
> > Is this normal, and to be expected, or is there some sort of quality
> > control knob I need to turn?
> >    
> 
> XvMC is garbage.  If you want to use 
> other-than-software-decoding-on-the-CPU, use VDPAU, which will do 
> decoding on the GPU.  You may have to buy a $20-$40 nvidia video card to 
> use VDPAU, if yours doesn't support VDPAU.
> 
> Mike
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